#!/bin/bash

a=10
b=20

rel=`expr $a + $b`
echo "a + b: $rel"

rel=`expr $a - $b`
echo "a - b: $rel"

rel=`expr $a \* $b`
echo "a * b: $rel"

rel=`expr $a / $b`
echo "a / b: $rel"

rel=`expr $a % $b`
echo "a % b: $rel"

if[$a==$b]
then
	echo "a dengyu b"
fi
if[$a!=$b]
then
	echo "a budengyu b"
fi
